Glass composition and member having the same on substrate

ABSTRACT

A glass composition having high refractive index, softening property at low temperature and small average thermal expansion coefficient, and a member provided with the composition on a substrate, are provided. The glass composition of the present invention has a refractive index (n d ) of from 1.88 to 2.20, a glass transition temperature (T g ) of from 450 to 490° C., and an average thermal expansion coefficient at temperatures from 50° C. to 300° C. (α 50-300 ) of from 60×10 −7 /K to 90×10 −7 /K, and includes Bi 2 O 3  in an amount of from 5 to 25% in terms of mol % on the basis of oxides.

TECHNICAL FIELD

The present invention relates to a glass composition having highrefractive index, softening property at low temperature and smallaverage thermal expansion coefficient, and a member provided with thecomposition on a substrate.

BACKGROUND ART

Conventionally, a glass composition having (1) high refractive index(refractive index at the d line is from 1.88 to 2.20), (2) low softeningtemperature (490° C. or lower) and (3) small average thermal expansioncoefficient (the average thermal expansion coefficient is (65 to90)×10⁻⁷/K), and a member provided with the glass composition on asubstrate (hereinafter referred to as “glass composition and the like)have not been present.

The glass composition and the like simultaneously provided with at mosttwo requirements of the above three requirements are proposed (PatentDocuments 1 to 5).

In recent years, environmental pollution becomes serious problem in themelting of a glass containing lead oxide. Therefore, the glass isrequired to not contain lead oxide.

BACKGROUND ART DOCUMENT Patent Documents

Patent Document 1: JP-A-2003-300751

Patent Document 2: JP-A-2003-160355

Patent Document 3: JP-A-2006-111499

Patent Document 4: JP-A-2002-201039

Patent Document 5: JP-A-2007-51060

SUMMARY OF THE INVENTION Problems that the Invention is to Solve

However, any of Patent Documents 1 to 5 does not disclose or suggest tobe simultaneously provided with the above three requirements. It isnecessary to be simultaneously provided with the three requirements inorder to form a high refractive index film on a soda lime substrate byfiring glass frit/glass paste. The glasses of Patent Documents 1 to 3are developed for use in precision press molding lens. For this reason,the glasses of Patent Documents 1 to 3 do not have the object to fire asa fit, and therefore have the problem that an average thermal expansioncoefficient is large.

The glass of Patent Document 4 contains a large amount of bismuth. Forthis reason, the glass of Patent Document 4 has the problems thatcoloration is large and an average thermal expansion coefficient islarge.

The glass of Patent Document 5 is developed for use in precision pressmolding lens. For this reason, the glass of Patent Document 5 does nothave the object to fire as a frit, and therefore has the problem that aglass transition temperature is high.

The present invention provides a glass composition having highrefractive index, softening property at low temperature and smallaverage thermal expansion coefficient, and a member provided with theglass composition on a substrate.

Means for Solving the Problems

A glass composition the present invention has a refractive index (n_(d))of from 1.88 to 2.20, a glass transition temperature (T_(g)) of from 450to 490° C., and an average thermal expansion coefficient at temperaturesfrom 50° C. to 300° C. (α₅₀₋₃₀₀) of from 60×10⁻⁷/K to 90×10⁻⁷/K, andcomprises Bi₂O₃ in an amount of from 5 to 25% in terms of mol % on thebasis of oxides.

A glass frit of the present invention has a refractive index (n_(d)) offrom 1.88 to 2.20, a glass transition temperature (T_(g)) of from 450 to490° C., and an average thermal expansion coefficient at temperaturesfrom 50° C. to 300° C. (α₅₀₋₃₀₀) of from 60×10⁻⁷/K to 90×10⁻⁷/K, andincludes Bi₂O₃ in an amount of from 5 to 25% in terms of mol % on thebasis of oxides.

A member of the present invention includes the glass composition or theglass frit having a refractive index (n_(d)) of from 1.88 to 2.20, aglass transition temperature (T_(g)) of from 450 to 490° C., and anaverage thermal expansion coefficient at temperatures from 50° C. to300° C. (α₅₀₋₃₀₀) of from 60 ×10⁻⁷/K to 90×10⁻⁷/K, and comprising Bi₂O₃in an amount of from 5 to 25% in terms of mol % on the basis of oxides.

Advantage of the Invention

According to the present invention, a glass composition having highrefractive index, softening property at low temperature and smallaverage thermal expansion coefficient, and a member provided with thecomposition on a substrate can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing a member having a glass frit fired layer formedon a glass or ceramic substrate.

FIG. 2 is a view showing a member containing scattering materials in theglass frit fired layer.

FIG. 3 is a view showing a member having a translucent electrode layerfilm-formed on the glass frit fired layer.

MODE FOR CARRYING OUT THE INVENTION

The refractive index (n_(d)) of the glass composition of the presentinvention is a range of from 1.88 to 2.20. When the refractive index isfallen in this range, the effect of extracting the emitted light islarge in the case of using as an organic LED scattering layer.

The refractive index (n_(d)) of the glass composition of the presentinvention is preferably from 1.95 to 2.10.

The glass transition temperature (T_(g)) of the glass composition of thepresent invention is from 450 to 490° C. When the glass transitiontemperature is fallen in this range, a substrate does not deform by atemperature even though the glass frit of the present invention is firedand softened on a soda lime glass substrate. The glass transitiontemperature (T_(g)) is preferably from 450 to 480° C., and morepreferably from 450 to 475° C. The glass transition temperature (T_(g))used herein is defined by the temperature corresponding to viscositycoefficient η of glass=10¹⁴ dPa·S.

The average thermal expansion coefficient of the glass composition ofthe present invention is from 60×10⁻⁷/K to 90×10⁻⁷/K in a temperaturerange of from 50 to 300° C. When the average thermal expansioncoefficient is satisfied with this requirement, even though the glassfrit of the present invention is fired and softened on the soda limeglass substrate, the glass frit does not break and the substrate doesnot greatly warp. The average thermal expansion coefficient attemperatures from 50 to 300° C. is preferably from 65×10⁻⁷/K to85×10⁻⁷/K, and particularly preferably from 70×10⁻⁷/K to 75×10⁻⁷/K. Theaverage thermal expansion coefficient is a numerical value measured witha thermo-mechanical analyzer (TMA).

The glass composition of the present invention contains P₂O₅, Bi₂O₃,Nb₂O₅ and ZnO as essential components, and can contain B₂O₃, Li₂O, Na₂O,K₂O, TiO₂, WO₃, TeO₂, GeO₂, Sb₂O₃ and alkaline earth metal oxides asoptional components.

The range of each component content is, in terms of mol %, 15 to 30% ofP₂O₅, 5 to 25% of Bi₂O₃, 5 to 27% of Nb₂O₅, 4 to 35% of ZnO, 0 to 17% ofB₂O₃, 0 to 14% of Li₂O, 0 to7% of Na₂O, 0 to 7% of K₂O, 0 to 13% ofTiO₂, 0 to 20% of WO₃, 0 to 7% of TeO₂, 0 to 7% of GeO₂, 0 to 2% ofSb₂O₃ and 0 to 10% of alkaline earth metal oxides, in which the totalcontent of alkali metal oxides is 14% or less.

In the components of the glass composition of the present invention,P₂O₅ is an essential component which forms a network structure becominga skeleton of a glass, and imparts stability to a glass. In the casewhere P₂O₅ is less than 15 mol %, the glass is easily devitrified. Inthe case where P₂O₅ exceeds 30 mol %, it becomes difficult to obtainhigh refractive index required in the present invention. The preferredrange thereof is 19 to 28 mol %, and further preferred range is 20 to 26mol %.

Bi₂O₃ is an essential component which imparts high refractive index andincreases stability of a glass, and in the case where the contentthereof is less than 5%, its effect becomes insufficient. At the sametime, Bi₂O₃ increases the average thermal expansion coefficient andadditionally increases coloration. Therefore, the content is 25 mol % orless. The preferred range thereof is 10 to 23 mol %, and furtherpreferred range of 13 to 20 mol %.

Nb₂O₅ is an essential component which imparts high refractive index andadditionally lowers the average thermal expansion coefficient, and inthe case where the content is less than 5 mol %, its effect becomesinsufficient. At the same time, Nb₂O₅ increases the glass transitiontemperature. Therefore, the content is 27 mol % or less. In the casewhere Nb₂O₅ exceeds 27 mol %, the glass transition temperature becomestoo high, and the glass is easily devitrified. The preferred rangethereof is 7 to 20 mol %, and further preferred range is 10 to 18 mol %.

ZnO is an essential component which greatly decreases the glasstransition temperature while suppressing excess increase in the averagethermal expansion coefficient, and additionally has the effect to imparthigh refractive index. In the case where the content is less than 4 mol%, its effect becomes insufficient. On the other hand, in the case whereZnO exceeds 35 mol %, devitrification tendency of a glass is increased.The content of ZnO is 4 to 35 mol %, preferably 16 to 35 mol % (7 to 17%in mass % indication), more preferably 21 to 35 mol % (9 to 17% in mass% indication), and particularly preferably more than 23 mol % and morethan 10 mass %, and up to 35 mol %. However, in the case of containingZnO in an amount of 21 mol % or more, it is preferred that TiO₂ is notsubstantially contained in order to avoid devitrification.

B₂O₃ is not an essential component, but has the effect of improvingmeltability of a glass. In the case where the content exceeds 17 mol %,devitrification and phase separation easily occur, and additionally itbecomes difficult to obtain high refractive index required in thepresent invention.

Li₂O has the effect of imparting devitrification resistance to a glassand additionally decreasing the glass transition temperature, but at thesame time, increases the average thermal expansion coefficient. In thecase where Li₂O is excessively contained, the average thermal expansioncoefficient becomes too large. Therefore, the content of Li₂O ispreferably 0 to 14 mol %, and more preferably 2 to 7 mol %.

Na₂O has the effect of imparting devitrification resistance of a glass,but depending of its content, the average thermal expansion coefficientis extremely increased. Na₂O can be contained in a range of 0 to 7 mol %(0 to 2.5% in mass % indication), but it is more preferred that Na₂O isnot substantially contained.

K₂O has the effect of imparting devitrification resistance to a glass,but depending of its content, the average thermal expansion coefficientis extremely increased. K₂O can be contained in a range of 0 to 7 mol %,but it is more preferred that K₂O is not substantially contained.

TiO₂ has the effect of imparting high refractive index, but depending onits content, the glass transition temperature is increased andadditionally, a glass is easily devitrified. TiO₂ can be contained in arange of 0 to 13 mol %. It is preferred that the content is 0 to 9 mol%, and it is more preferred that TiO₂ is not substantially contained.

WO₃ has the effect of imparting high refractive index without greatlychanging the average thermal expansion coefficient and the glasstransition temperature. However, when the content exceeds 20 mol %,coloration is increased, and additionally, a glass is easilydevitrified.

TeO₂ has the effect of decreasing the glass transition temperature whilesuppressing excess increase in the average thermal expansioncoefficient. However, TeO₂ is expensive and may corrode a platinumcrucible. Therefore, the content thereof is 7 mol % or less.

GeO₂ has the effect of imparting high refractive index, but isexpensive. Therefore, it is not preferred that the content exceeds 7 mol%.

Sb₂O₃ is effective as a refining agent, and further has the effect ofsuppressing coloration. Sb₂O₃ can be added in a range of 0 to 2 mol %.

The alkaline earth metal oxides (at least one kind of MgO, CaO, SrO andBaO) improve the stability of a glass. However, in the case where thoseare contained exceeding 10 mol %, the refractive index is decreased, andadditionally the average thermal expansion coefficient and the glasstransition temperature are increased.

The alkaline metal oxides have the effects of imparting devitrificationresistance to a glass and decreasing the glass transition temperature.Therefore, the total content thereof is preferably 14 mol % or less, andmore preferably 2 to 7 mol %.

Na₂O and K₂O particularly increase the thermal expansion coefficient, ascompared with Li₂O. Therefore, it is preferred that Na₂O and K₂O are notsubstantially contained and only Li₂O is used.

The glass composition of the present invention can contain SiO₂, Al₂O₃,La₂O₃, Y₂O₃, Gd₂O₃, ZrO₂, Ta₂O₃, Cs₂O, transition metal oxides and thelike in a range that the effect of the invention is not impaired. Thetotal content thereof is preferably less than 5%, and more preferablyless than 3 mol %, and it is further preferred that those are notsubstantially contained (the content is substantially zero).

The glass of the present invention does not substantially contain leadoxide (the content is substantially zero). Therefore, the possibility ofcausing environmental pollution is low.

The term “does not substantially contain” used herein means that thecomponents are not positively contained, and includes the case that thecomponents are incorporated as impurities derived from other components.

The glass composition of the present invention can be obtained by usingraw materials such as oxides, phosphates, metaphosphates, carbonates,nitrates and hydroxides, weighing those so as to achieve a desiredcomposition, mixing those, melting the mixture at a temperature of 950to 1,500° C. using a crucible of platinum or the like, casting the meltor pouring the melt in a space of a twin-roll, and rapidly cooling themelt. The melt may be slowly cooled to remove strain.

The glass frit of the present invention is obtained by grinding theglass composition obtained by the above method with a mortar, a ballmill, a jet mill or the like, and as necessary, classifying theresulting powder. The mass-standard average particle size of the glassfrit is typically 0.5 to 10 μm. The surface of the frit glass may bemodified with a surfactant or a silane coupling agent. The mass-standardaverage particle size is a particle diameter measured with a laserdiffraction type particle size distribution measurement method.

The member of the present invention is a member having a glass layerhaving a given composition formed on a glass or ceramic substrate, asshown in FIG. 1. The thickness of the glass layer is typically 5 to 50μm. The substrate used is preferably that the average thermal expansioncoefficient at temperatures from 50 to 300° C. (α₅₀₋₃₀₀) is from75×10⁻⁷/K to 90×10⁻⁷/K, and examples of the substrate include a sodalime glass and PD200, a product of Asahi Glass Co., Ltd. The surface ofthe substrate may be coated with a silica film or the like. The memberis typically obtained by kneading the glass frit with a solvent, abinder or the like as necessary, applying the mixture to the substrate,firing the coating at a temperature about 60° C. or more higher than theglass transition temperature of the glass frit to soften the glass frit,and cooling the glass frit to a room temperature. Examples of thesolvent includes α-terpineol, butyl carbitol acetate, phthalic acidester and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and examplesof the binder include ethyl cellulose, acrylic resin, styrene resin,phenol resin and butyral resin. Components other than the solvent andthe binder may be contained in a range that the object of the presentinvention is not impaired. In the case of using the binder, it ispreferred to include a step of firing the glass frit at a temperaturelower than the glass transition temperature to vaporize the binderbefore softening the glass frit, before softening the glass frit.

The member of the present invention can contain scattering materials inthe glass fit fired layer as shown in FIG. 2. However, it is importantthat the distribution of the scattering materials in the scatteringlayer decreases from the inside of the fired layer toward the surfacethereof. By this distribution, the probability that the scatteringmaterials are present in the surface layer of the glass frit fired layeris lower than the inside of the scattering layer, and as a result, aflat and smooth surface can be obtained. For this reason, in the case offorming, for example, an organic LED element, a translucent electrodelayer and an organic layer can be formed uniformly, and interelectrodedistance between reflective electrodes formed on the organic layerbecomes uniform. As a result, long life of an element can be attempted.There are the cases that the scattering materials are gas bubbles, areparticles of a material having a composition different from the glassfit, and are crystals precipitated from the glass frit. Those may be asimple body or a mixed state.

In the member of the present invention, as shown in FIG. 3, thetranslucent electrode layer can be formed on the glass fit fired layerby a film forming method such as sputtering. In the case of using as anorganic LED scattering layer, the refractive index of the translucentelectrode layer is preferably lower than the refractive index of theglass frit. By satisfying this requirement, the emitted light from theorganic layer can be extracted with good efficiency. The translucentelectrode layer is typically ITO (Indium Tin Oxide), and can further useSnO₂, ZnO, IZO (Indium Zinc Oxide) and the like.

EXAMPLES Examples 1 to 27

Composition of the glass in terms of mol %, refractive index (n_(d)),glass transition temperature (T_(g)), and average thermal expansioncoefficient (α₅₀₋₃₀₀) at temperatures from 50° C. to 300° C., in eachExample are shown in Tables 1 to 3. Composition in terms of mass %calculated based on the composition in terms of mol % is also showntherein. In each glass composition, when the glass transitiontemperature was 490° C. or lower and the average thermal expansioncoefficient was from 60×10⁻⁷/K to 85×10⁻⁷/K, the glass composition wasevaluated as “Good”. Particularly, when the glass transition temperaturewas 475° C. or lower and the average thermal expansion coefficient wasfrom 70×10⁻⁷/K to 75×10⁻⁷/K, the glass composition was evaluated as“Excellent”. Each glass composition was obtained as follows. Oxides,phosphates, metaphosphates and carbonates were used as raw materials ofeach component. The raw materials were weighted so as to achieve thecomposition shown in Table 1 after vitrification, and sufficientlymixed. The mixture was melted in an electric furnace at a temperaturerange of 950 to 1,350° C. using a platinum crucible. The melt was castin a carbon-made mold, and the resulting glass cast was cooled to thetransition temperature, immediately placed in an annealing furnace, andslowly cooled to a room temperature.

The refractive index (n_(d)), the glass transition temperature (T_(g)),and the average thermal expansion coefficient (α₅₀₋₃₀₀) at temperaturesfrom 50° C. to 300° C., of the glass compositions obtained were measuredas follows.

(1) Refractive index (n_(d))

After polishing a glass, its refractive index was measured with aprecision refractometer KPR-2000, a product of Kalnew, by a V blockmethod.

(2) Grass transition temperature (T_(g))

A glass was processed into a rod having a diameter of 5 mm and a lengthof 200 mm, and its glass transition temperature was measured with athermomechanical analyzer (TMA) TD5000SA, a product of Bruker AXS in atemperature rising rate of 5° C./min.

(3) Average thermal expansion coefficient (α₅₀₋₃₀₀) at temperatures from50° C. to 300° C.

A glass was processed into a rod having a diameter of 5 mm and a lengthof 200 mm, and its average thermal expansion coefficient was measuredwith a thermomechanical analyzer (TMA) TD5000SA, a product of Bruker AXSin a temperature rising rate of 5° C./min. When the length of the glassrod at 50° C. is L₅₀ and the length of the glass rod at 300° C. isL_(300,) the average thermal expansion coefficient (α₅₀₋₃₀₀) attemperatures from 50° C. to 300° C. is obtained by 60₅₀₋₃₀₀={(L₃₀₀/L₅₀)−1}/(300-50).

TABLE 1 Example 1 2 3 4 5 6 7 8 9 Mol % Mol % Mol % Mol % Mol % Mol %Mol % Mol % Mol % P₂O₅ 21.9 20.5 20.0 19.7 21.7 22.1 19.7 15.9 25.1Bi₂O₃ 15.7 14.7 17.3 14.2 15.6 13.9 12.9 20.9 16.4 Nb₂O₅ 16.7 19.0 13.915.0 16.5 14.8 13.7 12.0 17.3 ZnO 4.7 8.0 18.1 19.7 21.6 24.3 31.1 20.422.7 B₂O₃ 11.4 10.6 10.4 10.3 11.2 11.5 10.2 8.9 13.0 Li₂O 11.5 10.3 5.24.8 3.7 4.7 4.3 5.0 5.5 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.00.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 TiO₂ 8.7 7.7 6.9 7.4 0.0 0.0 0.0 7.7 0.0WO₃ 9.9 9.2 8.2 8.9 9.7 8.7 8.1 9.2 0.0 Other — — — — — — — — —component Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0Mass % Mass % Mass % Mass % Mass % Mass % Mass % Mass % Mass % P₂O₅ 16.115.1 14.6 15.1 15.7 17.0 15.8 11.1 19.0 Bi₂O₃ 37.8 35.6 41.6 35.7 37.035.0 34.0 47.8 40.8 Nb₂O₅ 22.9 26.2 19.1 21.5 22.3 21.3 20.6 15.7 24.6ZnO 2.0 3.4 7.6 8.7 9.0 10.7 14.3 8.2 9.9 B₂O₃ 4.1 3.8 3.7 3.9 4.0 4.34.0 3.0 4.8 Li₂O 1.8 1.6 0.8 0.8 0.6 0.8 0.7 0.7 0.9 Na₂O 0.0 0.0 0.00.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 TiO₂ 3.43.2 2.8 3.2 0.0 0.0 0.0 3.0 0.0 WO₃ 11.9 11.1 9.8 11.1 11.4 10.9 10.610.5 0.0 Other — — — — — — — — — component Total 100.0 100.0 100.0 100.0100.0 100.0 100.0 100.0 100.0 Content of 11.5 10.3 5.2 4.8 3.7 4.7 4.35.7 5.5 alkali metal oxide (mol %) n_(d) 2.00 2.02 2.01 2.00 1.99 1.961.95 2.05 1.97 T_(g) (° C.) 483 483 476 483 479 474 468 463 480 α₅₀₋₃₀₀81 76 77 73 72 72 75 84 73 (10⁻⁷/K) Evaluation Good Good Good Good GoodExcellent Excellent Good Good

TABLE 2 Example 10 11 12 13 14 15 16 17 18 Mol % Mol % Mol % Mol % Mol %Mol % Mol % Mol % Mol % P₂O₅ 27.7 25.8 24.3 21.9 20.0 21.1 19.3 25.019.3 Bi₂O₃ 16.4 16.8 15.3 14.3 23.0 15.1 22.3 6.4 22.0 Nb₂O₅ 17.4 17.916.2 15.2 11.2 16.0 10.8 17.3 15.2 ZnO 22.7 23.3 26.7 19.9 25.1 21.024.3 22.6 10.7 B₂O₃ 0.0 0.0 2.8 14.9 11.7 10.9 11.3 13.0 10.0 Li₂O 5.55.7 5.1 4.8 0.0 0.0 0.0 5.5 4.3 Na₂O 0.0 0.0 0.0 0.0 0.0 6.4 0.0 0.0 0.0K₂O 0.0 0.0 0.0 0.0 0.0 0.0 3.3 0.0 0.0 TiO₂ 0.0 0.0 0.0 0.0 0.0 0.0 0.00.0 10.6 WO₃ 10.3 10.5 9.4 9.0 9.0 9.5 8.7 10.2 7.9 Other — — Sb₂O₃ — —— — — — component 0.2 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0100.0 100.0 Mass % Mass % Mass % Mass % Mass % Mass % Mass % Mass % Mass% P₂O₅ 19.1 17.7 17.5 16.6 13.2 15.5 13.0 21.6 12.8 Bi₂O₃ 37.1 37.7 36.335.6 49.9 36.4 49.2 18.2 47.9 Nb₂O₅ 22.4 23.0 21.9 21.6 13.9 22.0 13.628.1 18.9 ZnO 9.0 9.1 11.1 8.7 9.5 8.8 9.4 11.2 4.1 B₂O₃ 0.0 0.0 1.0 5.53.8 3.9 3.7 5.5 3.2 Li₂O 0.8 0.8 0.8 0.8 0.0 0.0 0.0 1.0 0.6 Na₂O 0.00.0 0.0 0.0 0.0 2.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 1.5 0.0 0.0TiO₂ 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.9 WO₃ 11.6 11.7 11.1 11.2 9.711.4 9.6 14.4 8.6 Other — — Sb₂O₃ — — — — — — component 0.3 Total 100.0100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Content of 6.4 5.7 5.14.8 0 6.4 3.3 5.5 4.3 alkali metal oxide (mol %) n_(d) 1.99 2.01 1.991.96 2.00 1.97 1.99 1.89 2.08 T_(g) (° C.) 485 486 475 485 487 482 480490 488 α₅₀₋₃₀₀ 80 79 70 69 80 78 85 61 75 (10⁻⁷/K) Evaluation Good GoodExcellent Good Good Good Good Good Good

TABLE 3 Example 19 20 21 22 23 24 25 26 27 Mol % Mol % Mol % Mol % Mol %Mol % Mol % Mol % Mol % P₂O₅ 21.7 22.5 20.4 20.1 21.7 21.0 21.0 21.021.0 Bi₂O₃ 22.2 14.7 13.3 14.5 14.2 13.7 13.7 13.7 13.7 Nb₂O₅ 6.4 25.414.2 15.3 15.0 14.5 14.5 14.5 14.5 ZnO 27.2 11.5 18.5 9.6 19.6 19.0 19.019.0 19.0 B₂O₃ 12.7 11.7 10.6 10.4 11.3 10.9 10.9 10.9 10.9 Li₂O 0.0 5.04.5 8.3 4.8 4.6 4.6 4.6 4.6 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 TiO₂ 0.0 0.0 0.0 7.6 0.0 0.0 0.0 0.00.0 WO₃ 9.8 9.2 18.5 9.0 8.9 8.6 8.6 8.6 8.6 Other — — — TeO₂ GeO₂ MgOCaO SrO BaO component 5.2 4.5 7.7 7.7 7.7 7.7 Total 100.0 100.0 100.0100.0 100.0 100.0 100.0 100.0 100.0 Mass % Mass % Mass % Mass % Mass %Mass % Mass % Mass % Mass % P₂O₅ 15.0 15.3 14.8 15.1 16.4 16.7 16.7 16.416.3 Bi₂O₃ 50.5 32.9 31.7 35.6 35.3 35.8 35.7 35.2 34.8 Nb₂O₅ 8.3 32.419.3 21.5 21.3 21.6 21.5 21.3 21.0 ZnO 10.8 4.5 7.7 4.1 8.5 8.7 8.6 8.58.4 B₂O₃ 4.3 3.9 3.8 3.8 4.2 4.2 4.2 4.2 4.1 Li₂O 0.0 0.7 0.7 1.3 0.80.8 0.8 0.8 0.7 Na₂O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 K₂O 0.0 0.0 0.00.0 0.0 0.0 0.0 0.0 0.0 TiO₂ 0.0 0.0 0.0 3.2 0.0 0.0 0.0 0.0 0.0 WO₃11.1 10.3 22.0 11.0 11.0 11.2 11.1 11.0 10.9 Other — — — TeO₂ GeO₂ MgOCaO SrO BaO component 4.4 2.5 1.0 1.4 2.6 3.8 Total 100.0 100.0 100.0100.0 100.0 100.0 100.0 100.0 100.0 Content of 0 5 4.5 8.3 4.8 4.6 4.64.6 4.6 alkali metal oxide (mol %) n_(d) 1.98 2.02 1.98 1.99 1.95 1.951.95 1.95 1.95 T_(g) (° C.) 483 490 478 470 477 483 482 483 484 α₅₀₋₃₀₀82 68 72 85 73 77 81 81 84 (10⁻⁷/K) Evaluation Good Good Good Good GoodGood Good Good Good

Examples 28 to 31

The flake-like glass having each composition shown in Examples 1, 2, 4and 5 was weighed, mixed and melted in the manners as in Examples 1 to27, and its melt was poured in a space of a twin-roll and then rapidlycooled to prepare a flake. Each flake was dry ground with analumina-made ball mill for 1 hour to obtain each glass frit. The massmean size of each frit glass was about 3 μm. 75 g of each glass fritobtained was kneaded with 25 g of an organic vehicle (obtained bydissolving 10 mass % of ethyl cellulose in α-terpineol) to prepare aglass paste. The glass paste was uniformly printed in a size of 9 cmsquare on the center of a soda lime glass substrate having a size of 10cm square and a thickness of 0.55 mm, having a silica film coated on thesurface thereof such that the film thickness after firing becomes 30 μm,and then dried at 150° C. for 30 minutes. The temperature was oncereturned to room temperature, and increased to 450° C. over 30 minutes,followed by maintaining the temperature (450° C.) for 30 minutes.Thereafter, the temperature was increased to 550° C. over 12 minutes,followed by maintaining the temperature (550° C.) for 30 minutes.Thereafter, the temperature was decreased to room temperature over 3hours. Thus, a glass frit fired layer was formed on the soda lime glasssubstrate. Each substrate thus obtained was observed as to whetherbreakage occurs in the fired layer and the substrate. Furthermore, anaverage value of warpage of the substrate at four corners of the firedlayer was measured, and it was judged as to whether or not the warpagecan be allowable. When the average value of warpage exceeds 1.00 mm, itwas judged that the warpage is not allowable. The results are shown inTable 4. The average thermal expansion coefficient (α₅₀₋₃₀₀) attemperatures from 50° C. to 300° C. of the soda lime glass used is83×10⁻⁷/K.

TABLE 4 Example 28 29 30 31 Composition of Same as Same as Same as Sameas glass frit Example 1 Example 2 Example 4 Example 5 Breakage of NoneNone None None fired layer Breakage of None None None None substrateAverage value 0.72 mm 0.55 mm 0.00 mm 0.00 mm of warpage of (Allowable)(Allowable) (Allowable) (Allowable) substrate at four corners of firedlayer

Comparative Examples 1 to 10

Composition of the glass in terms of mol %, refractive index (n_(d)),glass transition temperature (T_(g)), and average thermal expansioncoefficient (α₅₀₋₃₀₀) at temperatures from 50° C. to 300° C., in eachComparative Example are shown in Table 5. Composition in terms mass %calculated based on the composition in terms of mol % is also shown inTable 6. In each glass, when the glass transition temperature is not490° C. or lower and the average thermal expansion coefficient is notfrom 60×10⁻⁷/K to 85×10⁻⁷/K, the glass was evaluated as “Poor”. Eachphysical value of the glasses prepared in the same manners as inExamples 1 to 27 was measured in the same manner as in Examples 1 to 27.The refractive index (n_(d)) of Comparative Example 9 could not bemeasured due to large coloration. Comparative Examples 1 and 2correspond to Examples 5 and 12 of the above-described Patent Document 3(JP-A-2006-111499), respectively, Comparative Example 3 corresponds toExample 3 of the above-described Patent Document 1 (JP-A-2003-300751),Comparative Examples 4 and 5 correspond to Examples 1 and 2 of theabove-described Patent Document 2 (JP-A-2003-160355), respectively,Comparative Examples 6, 7 and 8 correspond to Examples 1, 10 and 13 ofthe above-described Patent Document 5 (JP-A-2007-51060), respectively,and Comparative Example 9 corresponds to Example 3 of theabove-described Patent Document 4 (JP-A-2002-201039).

TABLE 5 Comparative Example 1 2 3 4 5 6 7 8 9 10 Mol % Mol % Mol % Mol %Mol % Mol % Mol % Mol % Mol % Mol % P₂O₅ 25.0 25.5 18.6 23.0 25.4 25.2925.41 26.26 0.0 23.1 Bi₂O₃ 8.0 20.0 5.5 6.7 6.6 5.39 4.71 4.74 42.7 16.6Nb₂O₅ 18.0 18.0 24.6 15.3 18.3 25.66 23.35 27.73 0.0 17.6 ZnO 1.0 0.00.0 0.0 0.0 0.00 0.00 0.00 28.5 0.0 B₂O₃ 2.0 2.0 9.8 0.0 0.0 0.00 0.000.00 28.7 5.5 Li₂O 18.0 6.0 7.6 10.5 8.1 18.02 16.43 18.43 0.0 11.6 Na₂O10.0 10.5 21.9 17.7 18.3 0.00 0.00 0.00 0.0 4.0 K₂O 2.0 2.0 0.0 0.0 2.91.91 1.91 1.96 0.0 2.5 Cs₂O 0.0 0.0 0.0 0.0 0.0 0.00 1.95 2.82 0.0 0.0Ti₂O 7.0 7.0 10.4 13.8 11.3 0.00 0.71 0.00 0.0 8.7 WO₃ 8.0 8.0 0.0 9.49.1 10.84 10.82 9.37 0.0 10.4 BaO 1.0 1.0 1.5 3.6 0.0 2.34 4.62 0.00 0.00.0 Sb₂O₃ 0.0 0.1 0.1 0.1 0.1 0.25 0.06 0.06 0.0 0.0 GeO₂ 0.0 0.0 0.00.0 0.0 10.30 10.03 8.63 0.0 0.0 Other — — — — — — MoO₃ — CeO₂ —component 0.01 0.1 Total 100.0 100.1 100.0 100.1 100.1 100.0 100.0 100.0100.0 100.0 Content of 30.0 18.5 29.5 28.2 29.3 19.9 18.3 20.4 0.0 18.1alkali metal oxides (mol %) n_(d) 1.91 2.00 1.90 1.92 1.90 1.94 1.911.92 - 2.01 Tg (° C.) 465 485 495 479 493 525 520 536 370 479 α₅₀₋₃₀₀104 103 108 115 115 72 77 73 102 92 (10⁻⁷/K) Evaluation Poor Poor PoorPoor Poor Poor Poor Poor Poor Poor

TABLE 6 Comparative Example 1 2 3 4 5 6 7 8 9 10 Mass % Mass % Mass %Mass % Mass % Mass % Mass % Mass % Mass % Mass % P₂O₅ 21.9 17.0 17.520.8 22.3 20.33 20.42 20.64 0.0 16.4 Bi₂O₃ 23.0 43.5 17.0 19.8 18.914.23 12.44 12.23 82.1 38.6 Nb₂O₅ 29.5 22.3 43.4 26.0 30.0 38.62 35.1440.82 0.0 23.4 ZnO 0.5 0.0 0.0 0.0 0.0 0.00 0.00 0.00 9.6 0.0 B₂O₃ 0.90.6 4.5 0.0 0.0 0.00 0.00 0.00 8.2 1.9 Li₂O 3.3 0.8 1.5 2.0 1.5 3.052.78 3.05 0.0 1.7 Na₂O 3.8 3.0 9.0 7.0 7.0 0.00 0.00 0.00 0.0 1.2 K₂O1.2 0.9 0.0 0.0 1.7 1.02 1.02 1.02 0.0 1.2 Cs₂O 0.0 0.0 0.0 0.0 0.0 0.003.62 5.13 0.0 0.0 Ti₂O 3.5 2.6 5.5 7.0 5.6 0.00 0.32 0.00 0.0 3.5 WO₃11.5 8.6 0.0 13.9 13.0 14.23 14.20 12.03 0.0 12.1 BaO 0.9 0.7 1.5 3.50.0 2.03 4.01 0.00 0.0 0.0 Sb₂O₃ 0.0 0.2 0.1 0.2 0.2 0.41 0.10 0.10 0.00.0 GeO₂ 0.0 0.0 0.0 0.0 0.0 6.10 5.94 5.00 0.0 0.0 Other — — — — — —MoO₃ — CeO₂ — component 0.01 0.1 Total 100.0 100.2 100.0 100.2 100.2100.0 100.0 100.0 100.0 100.0

Comparative Examples 11 and 12

Glass fits having each composition shown in Comparative Examples 1 and10 were prepared in the same manner as in Examples 28 to 31, and firedon the same soda lime substrates in the same manner. Each substrate thusobtained was observed as to whether breakage occurs in the fired layerand the substrate. Furthermore, an average value of warpage of thesubstrate at four corners of the fired layer was measured, and it wasjudged as to whether or not the warpage can be allowable. When theaverage value of warpage exceeds 1.00 mm, it was judged that the warpageis not allowable. The results are shown in Table 7. The average thermalexpansion coefficient (α₅₀₋₃₀₀) at temperatures from 50° C. to 300° C.of the soda lime glass used is 83×10⁻⁷/K.

TABLE 7 Comparative Example 11 12 Composition of Same as ComparativeSame as Comparative glass frit Example 1 Example 10 Breakage of PresentNone fired layer Breakage of Present None substrate Average valueMeasurement impossible 1.33 mm of warpage of due to breakage (Notallowable) substrate at (Not allowable) four corners of fired layer

This application is based on Japanese Patent Application No. 2009-014331filed on Jan. 26, 2009, the disclosures of which are incorporated hereinby reference.

The present invention makes it possible to produce a high efficientscattering light extraction member for particularly organic LED uses byapplying a glass composition having high refractive index, softeningproperty at low temperature and small average thermal expansioncoefficient to an optical member. Especially, according to the presentinvention, a glass frit suitable for a scattering layer which enables anorganic LED light extraction to improve can be provided. Furthermore,the glass frit of the present invention does not give deformation andunallowable warpage to the substrate after firing and softening on thesoda line substrate, and does not cause breakage. For this reason, theglass frit of the present invention can use a soda lime substrate as asubstrate of an organic LED scattering layer, and can reduce theproduction cost.

100: Glass or ceramic substrate

101: Glass layer or fired layer of glass frit

102: Scattering material

103: Translucent electrode layer

1. A glass composition having a refractive index (n_(d)) of from 1.88 to2.20, a glass transition temperature (T_(g)) of from 450 to 490° C. andan average thermal expansion coefficient at temperatures from 50° C. to300° C. (α₅₀₋₃₀₀) of from 60×10⁻⁷/K to 90×10⁻⁷/K, and comprising Bi₂O₃in an amount of from 5 to 25% in terms of mol % on the basis of oxides.2. The glass composition according to claim 1, comprising, in terms ofmol % on the basis of oxides: 15 to 30% of P₂O₅, 5 to 27% of Nb₂O₅, and4 to 35% of ZnO.
 3. The glass composition according to claim 2,comprising, in terms of mol % on the basis of oxides: 0 to 17% of B₂O₃,0 to 14% of Li₂O, 0 to 7% of Na₂O, 0 to 7% of K₂O, 0 to 13% of TiO₂, 0to 20% of WO₃, 0 to 7% of TeO₂, 0 to 7% of GeO₂, 0 to 2% of Sb₂O₃, and 0to 10% of alkaline earth metal oxides, wherein a total content of alkalimetal oxides is 14% or less.
 4. The glass composition according to claim2, which does not substantially contain Na₂O and K₂O.
 5. The glasscomposition according to claim 2, wherein the total content of thealkali metal oxides is 2 to 7 mol %.
 6. The glass composition accordingto claim 3, wherein a content of ZnO exceeds 23 mol % and exceeds 10mass %, and TiO₂ is not substantially contained.
 7. The glasscomposition according to claim 1, which does not substantially containlead oxide.
 8. A glass frit having the composition according to claim 1.9. A member provided with a glass layer having the composition accordingto claim 1 on a glass or ceramic substrate.
 10. A member provided with aglass layer obtained by firing the glass frit according to claim 8 on aglass or ceramic substrate.